This invention relates generally to fluid handling apparatus capable of self proportioning and more specifically to liquid purification or separation apparatus having this capability. It has particular application to septic systems.
Septic systems, while having limited use in municipal treatment, are the primary devices for treatment of sewage from individual residences. Generally, residential septic systems consist of a drain line, a settling tank and a drain field. Sewage introduced into the settling tank through the drain line undergoes sedimentation of suspended solids and bacterial decomposition of waste products. The sewage is thereafter communicated to a drain field for dispersal of the effluent over a land area sufficient to allow absorption of the liquid into the ground.
Where the rate of inlet flow through the drain line exceeds the processing capacity of a conventional septic system, several undesirable results may occur. The time being insufficient for sedimentation and decomposition to take place, the settling tank discharges unprocessed sewage into the drain field. Should the drain field be unable to absorb the liquid, surface seepage results having an objectionable odor and carrying pathogenic bacteria. In addition, where the inlet flow rate of sewage through the drain line exceeds the absorption rate of the drain fields, the liquid level in the settling tank can rise above the drain line opening. This causes back pressure and results in solids settling out in the drain line thereby clogging the inlet and blocking off further waste disposal.
Prior solutions have depended on increasing the size of the septic tank or drain field. Lack of available space or poor soil absorbency often make this impractical however.
It is therefore an object of the present invention to provide apparatus for a sewage system which compensates for a sewage inlet flow greater than the rate of absorption of the drain field.
It is another object of the present invention to provide increased sewage system capacity without increasing the size of the septic tank.
It is an additional object of the present invention to accept unprocessed sewage when the absorption rate of the drain field is less than the inlet flow rate of sewage, process the sewage when the sewage system load is sufficiently low to allow it, and discharge the processed liquid through the drain fields when the absorption rate of the drain field is greater than the inlet flow rate.
It is a further object of the present invention to provide additional storage volume when the inlet flow of sewage so demands, and apparatus for the reintroduction of the liquid so stored when the sewage system is better able to process it.